1. Field of the Invention
This invention relates to a component suction site-teaching system for teaching a location of a suction site (i.e. a site to be sucked by a vacuum nozzle) of an electronic component supplied to a predetermined pickup position to nozzle moving means for moving the vacuum nozzle.
2. Prior Art
In a mounter (electronic component-mounting apparatus) or the like, electronic components are sequentially fed e.g. in a state carried on a carrier tape to a forward end of a component-feeding device, and vacuum nozzles provided on a main block of the mounting apparatus are brought to a position facing the forward end of the component-feeding device from above, to pick up the electronic components one after another. In this sequential operation, the component-feeding device feeds the electronic components one after another to the pickup position at the forward end thereof with high accuracy. On the other hand, in the main block of the mounting apparatus, each of the vacuum nozzles is moved accurately in X and Y directions and brought to the pickup position. Actually, however, it is impossible to always bring the vacuum nozzle precisely to each electronic component supplied to the pickup position due to inevitable mounting errors of the component-feeding device removably mounted to the main block of the mounting apparatus. So long as the electronic component to be picked up has a large and flat suction surface, no failure of pickup occurs even if the location of a suction site of the electronic component is slightly deviated or offset from design values thereof. However, in picking up another type of electronic component, such as a surface-mount connector component, which has a suction surface thereof formed with asperities and a very small suction site, the slightest deviation of the location of the suction site from its design values may cause a failure of the pickup.
For this reason, in picking up electronic components of this type, the conventional mounter or the like requires the operator to bring the vacuum nozzle close to the electronic component visually align the nozzle with the suction site of the component, and then teach results of the visual alignment to a control system for controlling motion of X-Y stages of the apparatus. In this case, since the component-feeding device is capable of feeding electronic components accurately to the pickup position at the forward end thereof, the above alignment is only required to be carried out for an electronic component on the carrier tape which is first supplied to the pickup position.
However, in the conventional teaching method based on the visual alignment, the operator is required to manually operate the X-Y stages and a lift device to repeatedly move the vacuum nozzle (of the mounting head) in the X and Y directions and lift/lower the same vertically (i.e. in a Z direction), which is very time-consuming and effort-demanding.
It is a first object of the invention to provide a component suction site-teaching system which is capable of teaching a location of a suction site of an electronic component to be sucked by a vacuum nozzle, with high accuracy and ease.
It is a second object of the invention to provide a component suction site teaching method which is capable of teaching a location of a suction site of an electronic component to be sucked by a vacuum nozzle, with high accuracy and ease.
To attain the first object, according to a first aspect of the invention, there is provided a component suction site-teaching system for an electronic component-mounting apparatus including a vacuum nozzle having a nozzle end face for picking up an electronic component thereat by vacuum, the component suction site-teaching system comprising:
nozzle moving means for moving the vacuum nozzle in directions of X axis and Y axis;
image taking means for taking an image of the electronic component set at a pickup position;
image creating means for creating a graphical image of the nozzle end face of the vacuum nozzle from shape data of the vacuum nozzle;
display means for displaying on a screen thereof the image of the electronic component taken by the image taking means and the graphical image of the nozzle end face created by the image creating means, such that the graphical image of the nozzle end face is superimposed on the image of the electronic component;
image control means for moving the image of the electronic component and the graphical image of the nozzle end face relative to each other on the screen of the display means, thereby effecting alignment of the graphical image of the nozzle end face with an image of a predetermined site of the electronic component; and
suction site-teaching means for teaching to the nozzle moving means a location of the predetermined site of the electronic component the image of which has been aligned with the graphical image of the nozzle end face by the image control means, as a location of a suction site of the electronic component to be sucked by the vacuum nozzle.
According to this component suction site-teaching system, the image of the electronic component taken by the image taking means and the graphical image of the nozzle end face generated by the image creating means are superimposed one upon the other and moved relative to each other thereby effecting alignment of the graphical image of the nozzle end face with an image of a predetermined site of the electronic component, and then a location of the predetermined site of the electronic component the image of which has been aligned with the graphical image of the nozzle end face is taught to the nozzle moving means as a location of a suction site of the electronic component to be sucked by the corresponding vacuum nozzle. Therefore, the alignment between the suction site of the electronic component and the end face of the vacuum nozzle can be carried out on screen by using the two images, whereby it is possible to teach to the nozzle moving means a suction site on the electronic component which is determined with high accuracy such that there are no asperities or obstacles existing on a suction surface within the suction site of the component. Further, the operator can carry out the alignment accurately and speedily, based or a representation of the actual positional relationship between the component and the nozzle. It should be noted that the initial position of the graphical image of the vacuum nozzle with respect to the image of the electronic component on the screen may be arbitrary, or may be set based on design value data (i.e. a location of a suction site set before the teaching).
Preferably, the component suction site-teaching system further comprises image-taking center-designating means for designating a design value-designated component center of the electronic component as a center of a field of view of the image taking means when the image taking means takes the image of the electronic component, if there is a fear that an image of the electronic component taken by the image taking means with the center of the field of view of the image taking means set to a design value-designated suction site center of the electronic component may extend of f the field of view of the image taking means.
According to this preferred embodiment, it is possible to start operation for the alignment, on the precondition that the displayed image of the electronic component is an image of an approximately central portion of the electronic component, and at the same time, since the center of the electronic component substantially agrees with that of the screen, it is easy to grasp the total picture of the component. This provides a solution to a conventional problem that when a suction site of an electronic component is deviated or offset far from the center of the electronic component, if an image of the electronic component is taken by the image taking means with the center of the field of view thereof set to the suction site of the component, it is impossible to determine which portion of the whole electronic component is shown by the image of the electronic component, making it difficult to locate the suction site of the component (e.g. when there is a large displacement in location between a design value-defined suction site and an actually-desired or proper suction site). Further, it is possible to prevent faulty sensing of an electronic component by the image taking means from occurring due to displacement of the component from the field of view of the image taking means.
More preferably, the image control means includes center aligning means for moving, on the screen of the display means, the image of the electronic component taken with the center of the field of view of the image taking means set to the design value-designated component center designated by the image-taking center-designating means, thereby effecting alignment between a center of the image of the electronic component and a center of the screen, and the suction site-teaching means teaches to the nozzle moving means the center of the image of the electronic component which is aligned with the center of the screen by the image control means as an actual component center of the electronic component.
According to this preferred embodiment, it is possible to teach an actual component center of the electronic component to the nozzle moving means in advance. This makes it possible to compensate for a minute displacement in location of the suction site in the case of an electronic component having a suction site set to the component center, and on the other hand accurately set the suction site by applying the offset (offset amount) to the actual component center in the case of an electronic component having a suction site thereof offset from the component center.
Preferably, the component suction site-teaching system further comprises component center-calculating means for causing the image taking means to take images of two points at respective diagonally opposed corners of the electronic component, calculating a location of the component center of the electronic component from results of the image-taking of the two points, and then causing the image taking means to take the image of the electronic component with the center of the field of view of the image taking means set to the component center of the electronic component the location of which is determined by the calculation, if there is a fear that an image of the electronic component taken by the image taking means with the center of the field of view thereof set to a design value-designated suction site center of the electronic component may extend off the field of view of the image taking means.
According to this preferred embodiment, even an image of an electronic component which is too large to fit in the field of view of the image taking means can be displayed with a component center thereof in agreement with the screen center. Therefore, it is possible to carry out alignment between the image of the electronic component and a graphical image of a corresponding nozzle with ease whether the electronic component has a suction site thereof located at its component center (correction of a minute displacement is carried out, in this case) or offset from the same.
Preferably, the suction site-teaching means teaches the location of the component center calculated by the component center-calculating means to the nozzle moving means as an actual component center of the electronic component.
According to this preferred embodiment, it is possible to teach an actual component center of the electronic component to the nozzle moving means in advance. This makes it possible to compensate for a minute displacement in location of the suction site in the case of an electronic component having a suction site set to the component center, and on the other hand accurately set the suction site by applying the offset (offset amount) to the actual component center in the case of an electronic component having a suction site thereof offset from the component center.
Preferably, the graphical image of the nozzle end face is fixedly displayed in a central portion of the screen, and the image control means positions the image of the electronic component with respect to the graphical image of the nozzle end face, for the alignment.
This preferred embodiment enables the operator to position the image of the electronic component with respect to the graphical image of the vacuum nozzle while feeling as if the electronic component were moved toward the movable nozzle held in a fixed state, in agreement with the operator""s sense of motion of the sight line toward the nozzle. According to this embodiment, it is possible to dispense with processing for calculating the center of the electronic component from the image of the electronic component, which would be required in the case of the image of the electronic component being fixedly displayed in a central portion of the screen.
More preferably, the graphical image of the nozzle end face is displayed such that a point on the graphical image corresponding in location to an axis of the vacuum nozzle agrees with the center of the display screen.
According to this preferred embodiment, even when the vacuum nozzle has a plurality of nozzle holes or a nozzle hole offset from the central axis of the vacuum nozzle, it is possible to carry out the alignment by accurately grasping of the positional relationship between the axis of the nozzle and the nozzle hole(s), so that the operator can perform the aligning operation without feeling any sense of disorder. Further, this embodiment does not require correction of a data-defined position of the vacuum nozzle. Moreover, when the electronic component has a suction site in agreement with a component center thereof, the location of the suction site and the location of the component center can be taught simultaneously.
Preferably, the graphical image of the nozzle end face is formed by at least one of an outline of the nozzle end face and an outline of a nozzle hole.
According to this preferred embodiment, it is possible to use the graphical image flexibly in accordance with a shape of the electronic component. For instance, a different mode of the graphical image can be used in dependence on whether the alignment is required to be carried out with preference to a location of the nozzle hole, or with preference to the nozzle end avoiding asperities formed on a suction surface of the electronic component.
Preferably, the display means is capable of zooming in/out the image of the vacuum nozzle and the graphical image of the electronic component.
According to this preferred embodiment, even alignment requiring extremely high accuracy can be carried out easily by zooming in the images. On the other hand, even if the electronic component (component image) is too large to fit in the screen, it is possible to zoom out the image of the electronic component to display the whole thereof on screen, so that alignment can be carried out without any inconvenience.
Preferably, the component suction site-teaching system further comprises nozzle angle-designating means for designating a predetermined angle of rotation of the vacuum nozzle when the vacuum nozzle is required to be rotated through the predetermined angle about an axis thereof to pick up the electronic component, and the display means displays the graphical image of the nozzle end face after rotating the graphical image of the nozzle end face relative to the image of the electronic component through the predetermined angle designated by the nozzle angle-designating means.
According to this preferred embodiment, it is possible to carry out the alignment by using the graphical image representative of the real vacuum nozzle in its attitude taken immediately before picking up the electronic component, i.e. in a state after rotation. Accordingly, even if the vacuum nozzle is formed e.g. with two nozzle holes or a nozzle hole in the form of a slit, the alignment can be performed in a manner suitable for an attitude or orientation which the vacuum nozzle will assume after rotation for picking up the component.
More preferably, if the nozzle end face is too large for the graphical image thereof to be displayed within the screen of the display means assuming that the display means displays an outline of the nozzle end face, the display means displays only an outline of a nozzle hole of the vacuum nozzle on the screen thereof.
According to this preferred embodiment, it is possible to recognize a location of the nozzle hole on screen clearly, which facilitates the alignment.
To attain the second object, according to a second aspect of the invention, there is provided a method of teaching a suction site of an electronic component to be picked up by vacuum by a vacuum nozzle, the method comprising the steps of:
taking an image of the electronic component set at a pickup position;
creating a graphical image of a nozzle end face of the vacuum nozzle corresponding to the electronic component from shape data of the vacuum nozzle;
displaying the image of the electronic component and the graphical image of the nozzle end face on a screen, such that the graphical image of the nozzle end face is superimposed on the image of the electronic component;
moving the image of the electronic component and the graphical image of the nozzle end face relative to each other on the screen, thereby effecting alignment of the graphical image of the nozzle end face with an image of a predetermined site of the electronic component; and
teaching a location of the predetermined site of the electronic component the image of which site has been aligned with the graphical image of the nozzle end face, as a location of a suction site of the electronic component to be sucked by the vacuum nozzle, to nozzle moving means for moving the vacuum nozzle.
According to this component suction site-teaching method, the image of the real electronic component fed to the pickup position is captured to be displayed on the screen of the display means, then the image of the electronic component and the graphical image of the corresponding vacuum nozzle generated separately from the image of the electronic component are superimposed one upon the other for alignment or positioning between the two images, and results of the alignment are taught to the nozzle moving means in a feedback manner. Therefore, operation for teaching the location of the suction site of the component can be carried out easily and speedily, and with extremely high accuracy.
The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.